<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        class ButtonHandler {
            message = 'Button clicked'

            handleClick(){
                console.log(this);
            }

            handleClick1 = () => {
                console.log(this)
            }
        }

        const handler = new ButtonHandler()
        document
        .addEventListener('click', handler.handleClick1)
    </script>
    <button>click</button>
</body>
</html>